This is the GrimRacer 40x53 Metal Boat Propeller from AquaCraft.

Constructed of high quality Copper-Beryllium-Titanium material that is rigid but not brittle and can be sanded and shaped with less effort than stainless steel props Copper-Beryllium-Titanium material stays sharper longer and is less prone to dulling and chipping. True center bore hub with raised letters and numbering for easy identification. Tumbled to remove any excess cast flashing.

Specifications :
Diameter : 40mm
Pitch : 53 mm
Bore : 3/16 in.

This prop is Equivalent to the Octura 440 and the Prather 215 props.